The present invention pertains to methods for measuring physical characteristics of materials. More particularly, the present invention relates to methods for measuring elastic modulus (Young's modulus) of ceramic materials, including complex non-solid ceramics or glass-ceramics, through a range of temperatures.
Porous ceramic honeycomb structures are widely used as catalytic converter substrates and diesel particulate filters (DPFs). These structures may be formed from porous ceramic material, such as silicon carbide, cordierite or aluminum titanate. The earliest cordierite ceramic honeycombs for these applications consisted of reaction-sintered cordierite substrates prepared from extruded mixtures of talc, kaolin, calcined kaolin, and alumina. These were found to have suitable chemical durability, inertness, refractoriness, thermal shock resistance, and other properties for the application, and were cost effective to manufacture. Cordierite is a ceramic composition of the formula Mg2Al4Si5O18. Cordierite can exist in many crystalline forms including orthorhombic cordierite (orthorhombic Mg2Al4Si5O18 and its solid solutions), indialite (hexagonal Mg2Al4Si5O18 and its solid solutions), and mixtures thereof.
Recent trends in exhaust after-treatment for both gasoline and diesel engines have placed greater demands on converter and DPF materials. For converters, the shift toward higher cell densities and thinner walls has created material challenges in meeting requirements for strength and erosion resistance. The most recent applications requiring low cell densities and thin walls for reduced back pressure offer similar challenges, as does the growing interest in higher porosity converters with lower thermal mass for faster light-off to meet emission standards. Lower back pressure creates higher efficiency filters, while faster light-off reduces emissions when an engine is started and the filter is cold.
Demand for materials that can withstand these increasingly challenging conditions requires an increasingly detailed understanding of the chemical and physical characteristics of these materials under a wide range of conditions. In addition, it is desirable to understand the physical characteristics of materials during a manufacturing process, so that deviations from standard or desired characteristics can be identified early in a manufacturing process, to eliminate waste and improve quality control in manufacturing.